<template>
  <div>
    这是son
    {{ sum }}
    <el-button size="mini" @click="hclick">点我给 Son + 1</el-button>
  </div>
</template>

<script>
export default {
  props: {
    sum: {
      type: Number,
      required: true
    }
  },
  data() {
    return {

    }
  },

  mounted() {

  },

  methods: {
    hclick() {
      this.$emit('update:sum', this.sum + 1)
    }
  }
}
</script>

<style lang="scss" scoped>

</style>
